油罐软粘土地基性状

首先,通过K₀固结三轴试验等室内试验探讨了金山粘土的应力应变关系以及强度和刚度各向异性。采用有限单元法研究了圆形贮罐上部结构、垫层与地基共同作用以及土体各向异性对沉降的效应。其次,在试验研究的基础上,提出一组考虑初始应力状态和土体固有各向异性的非线性弹性系数实用方程式。通过强度发挥度,可以把土体刚度和强度联系起来。最后,应用比奥（Biot）固结理论有限单元法分析了二只大型油罐（容量分别为10000m³和30000m³）地基试水期间的固结过程,分析中考虑了上部结构、环基和垫层的刚度。计算沉降过程线和孔隙压力过程线与现场实测值接近。

Behaviour of the Soft Clay Ground under Tank

Firstly, the stress-strain relationship and anisotropies in strength and in stiffness of Jinshan clay are studied by the K0 consolidated triaxial tests and unconfined compression tests. The effects of the relative stiffness between tank and subsoil and the anisotropy of soft clay on the settlements are studied by finite element method.Secondly, based on the laboratory test results, the equations of nonlinear elastic parameters are developed, in which the effects of the initial anisotropic stress state and inherent anisotropy of the clay are considered. It is shown that the tangent modulus of the soil depends upon the mean effective stress and the strength mobilization, whereas the tangent Poissou's ratio depends upon the strength mobilization only. By means of the strength mobilization, the stiffness of soil may be related with the strength of soil.Finally, the consolidation process of the soft clay ground under two oil tanks, 10000m3 and 30000m3, in volume respectively, during the period of water test are analyzed based on Biot's consolidation theory by means of finite element method, the stiffness of the superstructure, ring wall and fills beneath tank being taken into account. The calculated settlements and pore water pressures agree well with the values obtained from the field measurement.